Low frequency hand held Moving Target Indicator (MTI) radars can be used in urban combat to gain situational awareness by locating personnel through dense obstructions such as walls. It is desirable that these sensors be small, lightweight, and low power. It is also highly desirable that they operate as hand held devices. However, such a radar device is very sensitive to small platform motions that are a result of hand held usage.
It has generally been accepted that highly sensitive sense through the wall (STTW) radars must be physically stationary to detect human targets exhibiting very slow and small movement such as postural sway or respiration. Typical means of stabilization for hand held devices have included pressing the device up against a wall through which the user is interested in gaining information. Stand-off sensors have typically been mounted on tripods or on stationary manned or unmanned robotic vehicles.
Typical approaches for radar motion compensation include the use of inertial sensors such as accelerometers to measure sensor displacement over time. In an STTW application, radial motion compensation accuracy to millimeter levels may support the detection of very slow and small movements associated with human postural sway or respiration. A hand held STTW sensor will typically exhibit small random radial motion consistent with the postural sway of the user. This small motion is difficult to accurately measure through the use of inertial sensing technology that meets the size and power requirement of the hand held STTW sensor application.